I bought a Tamron SP 35-80 f2.8-f3.8 for a while ago. This lens has received very good reviews on different forums, this is why I bought it and the price was right also. Focal length is just fine for use in a FF camera and the macro is almost “real” with 1/2.5 magnification. This lens is also very sharp through all the focal lengths, so no problem there. BUT. The anti-reflective coating on this lens is disgraceful. Virtually all the photos have a blue veiling haze on them, regardless if you use hood or not. This poor coating has also an effect on the light transmission, shutter times wide open (f/2.8) are the same as f/4 on other lenses.

Does anybody have any experience with this lens? I don’t understand the praise if the lens is unusable even if it is sharp. Or is there a way to overcome this problem by some kind of filter etc.?

This flare is even more obvious in daylight, but daylight is something we don’t have too much in Finland this time of the year. The first picture is taken with Canon EF 24-85mm f/3.5-4.5 USM and the second one with the Tamron SP 35-80mm 1:2.8-3.8. Optics are clean without any form of fungus or degradation. I do have lenses in much worse condition without these symptoms. I´m starting to believe that my lens is not faulty but the digital sensor and this lens don´t come along somehow. I´m using this lens with Canon EOS 5D II and Sony NEX-5n.

Mine behaves this way as well, but only if it is exposed to direct light such as the sun, or a light bulb.

The very first shot I took with it was in my mother's kitchen. The shot was backlit by bright light coming through the window. Terrible "blue glow". Just awful. If I am not careful, that's what I get from it.

As you say, it is otherwise an excellent lens, which is why I keep it. If you avoid situations that exacerbate the issue, it works great.

Granted, I would use it a whole lot more if it didn't have this issue. I somtime wonder if it would be better if all the coating was polished right off. I'd rather have "grey glow" than "blue glow".

Either way, I've managed to get the following results out of it...

I remember when I composed the last shot, I could see the glow because a spot of sun was touching the lens. I stepped to the right about 3 inches and it vanished.